somedude's VSS problems ... some recent testing results

[HotRodKid]

right now, alex has:

1) a vss that gives off a signal when rotated by hand
2)new wiring from the vss to the ecu
3) a new vss, i think this may even be his 3rd one
4) a different ECU in his car

now mind you, thats the entire system as far as the VSS is concerned, except for the pigtail for the vss

Our friend had a crazy thought... what if the tweecer is actually the problem? So i asked Alex when the VSS FIRST started acting up

"the problems started with teh FPS tranny when the tweecer was installed"

SOAB !

Obviously its not the FPS tranny's fault, cause it doesn't exist anymore

thoughts ?

 

[SHOZ123]

Have you monitored the VSS input to the PCM with a voltmeter in real time?

 

[gmorrell]

Can you be more specific about the VSS problems? Shift strategies not right, cruise not working, etc?

 

[HotRodKid]

shifts at 3K, doesn't downshift into teh proper gear when slowing, no cruise controll, tweecer datalog shows random speeds, changing WHATS datalogged changes what speed is displayed,

for example, sitting in my driveway yesterday the VSS showed 1 mph, alex changed what was selected in the payload and the VSS then read 50mph on cal con

the VSS hasnt been monitored in real time yet, its one of the things thats planned for today

 

[hawkeye18]

You're sure you're running a D4U1 strategy?

Are the contacts clean? Ford puts approximately seven inches of protective goop over the J3 terminal (ok, not really seven inches, but you get the idea) and if you don't clean it off with alcohol or whatever then you'll get some really funny results... kinda like the ones you're describing.

Write a tune on the tweecer. Disconnect and reconnect the tweecer. Now, read the tweecer. is the tune the same? If it is, chances are good it's not the tweecer.

 

[HotRodKid]

d4u1 strategy, check

contacts have been cleaned so many times its not even funny

tweecer has been taped in tighter so many times its not even funny

the tune itself never goes to ****, and the ecu is obeying the tune we have on the tweecer

 

[hawkeye18]

You might try loading a straight D4U1.BIN file on position 3 or something to let it run a baseline through the TwEECer and see if it causes the same issue to see whether it's in the tune or not.

 

[somedude_001]

just a update. I returned the car to stock for a few days and removed the tweecer. The only thing I noticed is 1 the cams give a incredibly lumpy idle at 800rpm (which is oh so sexy) and 2 the car gets incredible mileage when it doesn't make any power!

once the car was returned to stock I was not able to pull codes. jumping to 2 pins to start the KOEO and KOER tests did nothing. the car was completely unresponsive to jumping the pins. I don't know where to go from here. I put the turbo stuff back on the car and raised the boost for dyno day coming up next friday then off to south carolina for a few days, then to florida, then to NH for the convention, and finally back home to buffalo NY. I am not looking forward to the mileage this car is going to get but it should be... well it will be something all right.

I have this standing joke with my friends. S.H.O. ... Always a adventure! Will be close to 2000 miles round trip that is why I was hoping to get the tranny fixed because manual shifting gets old fast and not having a converter lock KILLS mileage.

 

[Sho Amo]

how about the TSS? ive heard of people having problems with that.

im not an automagic tranny kinda guy tho, i need a clutch

 

[HotRodKid]

pulled the PCM harness, tested the resistance of the VSS - 275 ohms or so, that's within spec

pierced the VSS wires near the ecu with some pins, tested resistance at the pins, 275 ohms, thats good, were hitting copper like we need to

reconnected the harness, put teh car in gear, set the meter for AC voltage and made a pull through the gears (car on stands) voltage output got as high as 9 or so, and is obviously following a distinct pattern based on rpm / current gear

tested resistance between battery negative and every ground terminal in sight, all show nearly nothing for resistance, also checked numerous "oddball" places on the engine and trans .... all showed nearly no resistance ... usually a fraction of an ohm

so VSS is good, grounds are good, and the tweecer isnt the problem ... what next ?

 

[HotRodKid]

and add in the previously swapped pcm, and teh factthat i gave the 2 terminals for the vss a slight tweek @ the pcm connector to make sure they were getting proper connection , and im stumped ...

 

[SeanMc]

Possibly something to do with the 3.99 gearing?

 

[SHOZ123]

That's 3.98.... Don't push it.

 

[somedude_001]

Possibly something to do with the 3.99 gearing?

I don't think so. I remember having this problem before I changed the gearing. adjusting the settings in the tweecer to the corrected numbers give to me last year or maybe the year before did nothing to correct the converter lockup issues related to the gearing change.

 

[rubydist]

Try re-routing some of the wiring between the vss and the pcm. It could be that you have some cross-wire interference going on with the way the wires are routed.

 

[HotRodKid]

now were looking into the TSS

teh ford dealer sasy the TSS adn Vss work together to determine speed....hmmm

old TSS: 132 ohms high
new Tss: 131 ohms high

Old TSS: 94 ohms low (tapping it against steel)
New Tss: 71 ohms low (tapping it against steel)

i wonder if 90 ohms isnt low enough for the PCM to see it switching ?

well find out, im fixing alexs exhaust before we restart the car

 

[somedude_001]

negative. That did not solve anything. we are back to being clueless on a solution.